12v battery keeps draining - parasitic drain?

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d3matt

Member
Joined
Oct 11, 2017
Messages
9
Location
Oxford, UK
Hi guys. I have a Peugeot iOn where the 12v battery keeps being drained flat in 3-4 days. Also have a new 12v battery fitted and still does the same. So have two good (and tested) batteries.
So been testing to see what is draining the battery. I've found the standby current drain is 0.3A and this reduced to 0.19A current drain when the vehicle is shutdown. I believe this should be less than 0.05A, well for ICE vehicles - I assume the same for the i-MiEV?
I've tested each circuit in the vehicle by removing every individual fuse (46 fuses) from all 3 fuse boxes and the 0.19A current remained.
I've also disconnected the radio harness and checked the door switches.
I've also cleaned the battery earth connection and terminals.
Also looked at the fault codes and everything looks fine.

So anyone know what to check next?
 
That is definitely too high, it will draw about 5AHr in one day and our little aux battery is only good for about 20-35, so it will flatten it in a hurry.

Usually everything has a fuse or a fusible link.

Are there any aftermarket equipment installed, e.g. radio, camera, heater? Maybe someone added a circuit directly from the aux battery + terminal--take a look to see.
 
d3matt said:
...So been testing to see what is draining the battery. I've found the standby current drain is 0.3A and this reduced to 0.19A current drain when the vehicle is shutdown....
By 'standby' I take it to mean the key is turned to the first position?
The ammeter is inserted directly between one of the battery terminals and the wire which attaches to it?
Agree with kiev, that every circuit is fused so 190ma with the car shut down is not normal.
Oh, and I moved this thread over to the Battery subforum.
 
Kind of obvious, but the dome lights are OFF when testing current, right? They are incandescent lights from the factory.

I can't remember what the cable looks like, but there should be a bunch of wires that all attach to the positive battery clamp. One of these wires comes directly from the DC-DC converter, bypassing both fuse blocks. Maybe disconnect that and see if the drain goes away?
 
It seems like a stuck relay, maybe the contacts have welded together and its not able to open and shut off the circuit. Pull the relays one by one to find the culprit. e.g. the windows can be rolled up within about 20 seconds after you turn off the key due to a timer circuit that keeps power for that function. Some circuit on a fusible link that has a relay downstream.
 
kiev said:
That is definitely too high, it will draw about 5AHr in one day and our little aux battery is only good for about 20-35, so it will flatten it in a hurry.

Usually everything has a fuse or a fusible link.

Are there any aftermarket equipment installed, e.g. radio, camera, heater? Maybe someone added a circuit directly from the aux battery + terminal--take a look to see.

No all stock with no mods or additions.
 
JoeS said:
d3matt said:
...So been testing to see what is draining the battery. I've found the standby current drain is 0.3A and this reduced to 0.19A current drain when the vehicle is shutdown....
By 'standby' I take it to mean the key is turned to the first position?
The ammeter is inserted directly between one of the battery terminals and the wire which attaches to it?
Agree with kiev, that every circuit is fused so 190ma with the car shut down is not normal.
Oh, and I moved this thread over to the Battery subforum.

Sorry, no...when I said "standby" I meant the car is locked and shutdown, but possibly not full asleep. Pulling the radio or interior fuse (joined together in a frame) will cause the current to rise to 0.3A, then drop back to 0.19A after about 1 minute.
Yes the ammeter is in series with the battery negative.
 
PV1 said:
Kind of obvious, but the dome lights are OFF when testing current, right? They are incandescent lights from the factory.

I can't remember what the cable looks like, but there should be a bunch of wires that all attach to the positive battery clamp. One of these wires comes directly from the DC-DC converter, bypassing both fuse blocks. Maybe disconnect that and see if the drain goes away?

Yes done lights are off as the door switch is clamped shut. Car locked and asleep.

Good idea about the DC-DC feed wire. I will look at that.
I can't see it is that though, as that would be charging the battery, not draining it. Unless there is a fault in the inverter.
 
kiev said:
It seems like a stuck relay, maybe the contacts have welded together and its not able to open and shut off the circuit. Pull the relays one by one to find the culprit. e.g. the windows can be rolled up within about 20 seconds after you turn off the key due to a timer circuit that keeps power for that function. Some circuit on a fusible link that has a relay downstream.

I did try pulling some relays. But I assumed that every relay circuit would also have a fuse so by pulling all the fuses, would indeed identify the circuit with the drain. If I could find that circuit, then I would look at the fuses. But I can't find that circuit as all 46 fuses didn't reveal any drop in the current drain at the battery.
 
headlight relays, tail light relays, any relays associated with the Brakes, the ABS, the ACS and the EV-ECU. These are all on fusible links without a tiny fuse in the box.

Also the keyless entry/immobilizer is not clearly defined that i can find in the manual.

Good luck i know it's tough to chase those down.
 
One more idea, Are you sure you do not have the ODB Link LX connected?
However 190mA looks too much for it, however it could take active some other car parts.
 
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